This invention relates to a method of safely extending the storage life of foods, particularly those susceptible to contamination and spoilage, as for example, chicken salad, custard-filled foods and fish fillets. In particular this invention relates to a method for treating such foods so as to not only extend the storage life but also inhibit the growth of common food-borne disease organisms, as for example, Staphylococcus and Salmonella species.
It should be noted that while this invention relates principally to easily spoiled foods as above, it is not intended for use with cultured food products such as creamed cottage cheese, cultured buttermilk, yogurt and the like. Such cultured food products are intended and do contain a substantial microbiological population when sold and present entirely different problems with respect to contamination and spoilage.
The food products with which the present invention is primarily concerned are very susceptible to both the growth of spoilage organisms and the growth of food-borne disease organisms. Thus, it has heretofore been exceedingly difficult to handle in satisfactory commercial manner such products as custard pies, eclairs, battered fish fillets, potato salad, egg salad, cooked lobster meat, cooled peeled shrimp, chicken salad, crab meat salad, and tuna salad because of rapid spoilage even when under refrigeration. Part of the problems with regard to such foods has been the difficulty in proper initial handling of the foods and the growth of food-borne disease organisms and spoilage organisms through many sequences in the cycle of preparation and storage. Further, it is difficult with respect to such foods to provide any microbial reducing treatment, as for example, sterilization or pasturization without seriously impairing the flavor or texture of the food.
Proposals have been made in the past for treating food with non-toxic acidic chemicals which metabolize readily. Thus, in U.S. Pat. No. 2,711,976, amino acids such as glycine or serine are suggested to increase the resistance of custard foods to spoilage organisms and Staphylococcus. U.S. Pat. No. 2,898,372, suggests calcium acetate propionate to reduce the mold in bread. U.S. Pat. No. 2,866,819 refers to the use of sorbic acid as a fungistat and preservative in foods generally. U.S. Pat. NO. 2,910,368 discloses the use of EDTA with sorbic acid to increase the shelf life of vegetable salads containing an acidic edible dressing. U.S. Pat. No. 2,992,114 suggests sorbic acid and mild heat treatment for the preservation of fruit and vegetables. U.S. Pat. No. 3,021,219 proposes sorbic acid to prevent mold in bread.
In a paper published in Applied Microbiology, Volume 18, pages 68-75 (July, 1969), Preonas et al reported on the use of a mixture of sorbic acid and propionic acid to retard the growth of Staphylococcus aureus on the top and cut surfaces of Southern Custard Pies. Although some retardation was found, it was noted that inhibition was affected by the moisture gradient so that the package would require refrigeration after opening. Further, there was evidence of mold formation after nine days. However, such prior art chemicals, used as described, could extend the storage life of the foods so as to permit growth of Clostridium.
One object of the present invention is to provide a novel method of safely extending the storage life of foods.
A further object of this invention is to provide such a method which is particularly adapted to foods highly susceptible to contamination and spoilage.
Another object of this invention is to provide such a method which concurrently inhibits the growth of common food-borne disease organisms.
A further object of this invention is to provide a preservative material for safely extending the storage life of foods.
Another object of this invention is to provide such a preservative material which also inhibits the growth of common disease-born organisms.
Other objects and advantages of this invention will be apparent from the description and claims which follow.